1. Field of the Invention
The present invention is related to a structure of fully enveloped miniature lamp bulb for lamp strings, and especially to such a structure capable of rendering assembling, shaping and mass production of miniature lamp bulbs more convenient and faster, and making appearance of them more variant.
Such a fully enveloped miniature lamp bulb of the present invention is directed to a miniature decorative lamp bulb which is not yet inserted into a lamp receptacle but has its electrode pins exposed to connect conductors directly for lightening or flashing.
2. Description of the Prior Art
In a conventional miniature lamp bulb, as shown in FIG. 1, when assembling in a factory, an exterior heat-shrinking pipe 12 is fixed on the joint of a miniature lamp bulb 10 and a pair of conductors 11. Process for assembling the interiors of the miniature lamp bulb 10 includes welding between the electrode pins and the conductors 11, and injection of adhesive anget after an inner plastic pipe is slipped over thereon, then the exterior heat-shrinking pipe 12 is fixed by way of heat shrinking. Such process of assembling not only is time consuming and cumbersome, but also is slow in processing which does not meet the requirement of mass production. Moreover, the exterior heat-shrinking pipe 12 fixed on the area between the soft miniature lamp bulb 10 and the conductors 11 by heat shrinking often makes uneven shrinkage and results ugly appearance on the whole product.
In view of this, an improvement as shown in FIG. 2 has been proposed, wherein, a miniature lamp bulb 13 is connected with a pair of conductors 14, a positioning block 15 is interposed between the conductors 14 at the joint of the lamp bulb 13 and the conductors 14. They are wholly placed in a die to be injection enveloped with a transparent cover 16. The advantage of such design is that, after assembling of the lamp bulb 13 with the conductors 14, appearance on the whole product can be neater and good-looking. And their assembling and enveloping can be done in the die, hence speed of processing is evidently faster. However, this measures is disadvantageous in that, the miniature lamp bulb and part of the conductors must be placed in the die to be injection enveloped. In production, the sequential injection and envelopment can not be proceeded until completing the primary assembling of the lamp bulb with the conductors into a semi product. According to the molding technique available now, such shaping method by injection and envelopment can only have limited amount of products completed each time. And by influence of the die for injection and envelopment, modeling of the transparent cover is limited and hardly changeable.
The object of the present invention is to provide a structure of fully enveloped miniature lamp bulb for lamp strings, with which, a plastic die is used in the first place to give a transparent cover with a desired contour. The transparent cover is provided with an assembling hole extending inwardly for a suitable depth from one end thereof and with a diameter coincident with that of the miniature lamp bulb. A positioning block is interposed between the conductors at the joint of the lamp bulb and the conductors for supporting the bottom of the miniature lamp bulb and leading the conductors to be connected. The assembled members as a whole then are placed in the assembling hole, PVC is well filled from the bottom of the assembling hole to complete assembling of the miniature lamp bulb.
The aforesaid transparent cover can be formed with a normal plastic die, thereby mass production can be even much faster and more convenient.
In the process of production in a factory, connecting of the miniature lamp bulb with the conductors and injection shaping of the transparent cover can be separately but synchronically proceeded to increase speed of production.
The contour of the transparent cover can be conveniently of any of various shapes, so that modeling of the transparent cover is varied.
The transparent cover can more suit the light converging surface provided at the location where the miniature lamp bulb locates to increase decorative effect.
The present invention will be apparent in its novelty and features after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings.